hfsnojournal.c

/*
 *      Disables hfs+ journal
 *      origin: http://dmunsie.wordpress.com/code/hacks/
 *
 *      compiles on linux
 */

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/mman.h>
#include <fcntl.h>
#include <byteswap.h>

int
main(int argc, char *argv[])
{
    int             fd = open(argv[1], O_RDWR);

    if (fd < 0) {
        perror("open");
        return -1;
    }

    unsigned char  *buffer =
        (unsigned char *) mmap(NULL, 2048, PROT_READ | PROT_WRITE,
                               MAP_SHARED,
                               fd, 0);

    if (buffer == (unsigned char *) 0xffffffff) {
        perror("mmap");
        return -1;
    }

    if ((buffer[1024] != 'H') && (buffer[1025] != '+')) {
        fprintf(stderr, "%s: HFS+ signature not found -- aborting.\n",
                argv[0]);
        return -1;
    }

    unsigned long   attributes = *(unsigned long *) (&buffer[1028]);
    attributes = bswap_32(attributes);
    printf("attributes = 0x%8.8x\n", attributes);

    if (!(attributes & 0x00002000)) {
        printf
            ("kHFSVolumeJournaledBit not currently set in the volume attributes field.\n");
    }

    attributes &= 0xffffdfff;
    attributes = bswap_32(attributes);

    *(unsigned long *) (&buffer[1028]) = attributes;
    buffer[1032] = '1';
    buffer[1033] = '0';
    buffer[1034] = '.';
    buffer[1035] = '0';
    buffer[1036] = 0;
    buffer[1037] = 0;
    buffer[1038] = 0;
    buffer[1039] = 0;

    printf("journal has been disabled.\n");
    return 0;
}